MILFORD -- His childhood friend dying in their school corridor, Christopher Plaskon dropped the knife and calmly walked to the principal's office in Jonathan Law High School, the police report released Tuesday states.

"I did it, just arrest me," he told the school's resource officer.

Police said Plaskon confessed to stabbing 16-year-old Maren Sanchez to death in Jonathan Law High School and he now he will stand trial as an adult.

Plaskon, 16, who classmates have said killed Sanchez on Friday because she wouldn't go to the junior prom with him, was arraigned on murder charges at a local medical facility.

The details of the killing were released as students returned to school Tuesday for the first time since the stabbing.

"Chris remains in the custody of the Department of Correction in the locked hospital psychiatric ward," his lawyer, Richard Meehan, said. "The name of the institution is being withheld, not only for his privacy but also that of the hospital staff and other patients."

Superior Court Judge Frank lannotti went to Plaskon's room at the facility with State's Attorney Kevin Lawlor, Meehan and a state court reporter, advised Plaskon of his constitutional rights and then made a finding there was probable cause for his arrest. He then ordered Plaskon held on $3 million bail.

According to the Milford Police Department's probable cause statement, at about 7:10 a.m. on Friday Officer James Kiely, the high school's resource officer, was called to the principal's office where he saw Plaskon with bloody hands and clothing. The report stated that Kiely, who knows Plaskon, asked him what happened and the boy confessed. Kiely handcuffed Plaskon and then went to the crime location in the hallway where he saw Sanchez was in grave condition.

The report says a teacher saw Plaskon on top of Sanchez during the attack and unsuccessfully tried to pull him off her. Another witness pointed out the bloody knife to officers where Plaskon dropped it, a short distance down the hallway.

The judge ordered Plaskon placed on a suicide watch and noted that he be allowed to take medication prescribed for him.

Plaskon is due in court in Milford Friday morning. At that time he is not expected to enter a plea. Instead the judge will set a date for a probable cause hearing.

As the students of Jonathan Law High School headed back to class on Tuesday, still badly shaken by the events of Friday morning, they were surrounded by therapy dogs, grief counselors, police officers, firefighters and scores of city officials.

They had no shortage of reminders of the tragedy when they arrived at school. Media trucks packed the side streets adjacent to the Law High. Most of the students wore purple, and purple ribbons and balloons seemed to be everywhere, too.

"So much purple," tweeted a student.

"We had a great showing of support by many, many members of the community throughout the school day," said Mayor Benjamin Blake, who was in the school throughout much of the morning. "It was as normal a start to the school day, at least from my estimation, as they could have had. But they are still shaken. The entire city is still shaken."

Blake said that even canines at Law High were there to soften the shock.

"There were therapy dogs, and their handlers, in force," Blake said. "We also had members of our human services agencies there, too."

Principal Fran Thompson set in place a full eight-period schedule so that the students would be in contact with most of their teachers. Also, the junior class, the class of the victim, met together for Period 8 on Tuesday.

Thompson told the students that they would have to rely in one another to get through these next few days.

"The teachers will need you and you will need them," he said. "We all feel sad and angry and guilty and confused, and that's OK," he said.

There was one sign of normalcy: Lunch selections were a turkey, ham, and cheese panini or a pizza bar with a choice of salad.

But it will be a long time before things are really normal again.

Calling hours for Maren Sanchez will take place on Thursday from 2 to 7 p.m., at the Cody-White Funeral Home, 107 Broad St. A shuttle service will be available beginning at 4 p.m. from the Parsons Complex about four blocks away. There will be no services.

On Monday, friends of Sanchez asked that students wear their prom dresses and tuxes to her calling hours Thursday according to a Twitter feed from in the Jonathan Law High School newspaper, "The Advocate."